Sure, if you want to include the OGL!
Well, yes, you can definitely because it's under OGL. Actually re-reading the OGL, I noticed that you would have to staple it to your finished product, but you're not actually compelled to license anything of your own under the OGL.
But do you have to?
Game mechanics in and of themselves are not typically covered under intellectual property laws, but the text of games themselves are. Similarly, there are a lot of branding things that WoTC considers to be theirs: if you look at the things explicitly held as their property in the OGL and extrapolate from there you can pretty easily stumble onto their toes.
The Str/Con/Dex/Int/Wis/Cha system may be so iconic that it is difficult to defend, though you could always use renamed versions to be strictly in the clear; Brawn/Toughness/Speed/Smarts/Prudence/Looks isn't quite as catchy, but definitely won't get you sued and a lot of people would get the wink-wink nudge-nudge true meaning.
That said, it's small enough that either it is unlikely to be considered infringement worthy of action in a court of law, or that it is something that they are unlikely to deal with.
The usual advice I give, however, is that if you're not certain, avoid the issue. A block of six stats that govern similar things is definitely in the clear, copying D&D's is a very light shade of grey but when you're dealing with Hasbro lawyers it may be in your best interest to stay pretty conservative.
As a general rule, and, again, not being a lawyer or giving legal advice, you'd probably only see this matter come up if there were some other point of concern with regards to infringement. For instance, if your experience point tables looked exactly like WoTC published work, you had a level system that was oddly similar, and you kept including elements that looked like they had been taken verbatim.
I'm not sure entirely what the guiding light for this matter is: I know that there has been at least one case (and I've lost my copyright casebook or I'd look up what it was), where some people wrote a book for one company, and then the next year published a very similar book for another company. They'd used the same research, and even though they'd "rewritten" the book, there were found to be substantial similarities between the two and the second book was found to infringe the copyright of the first.
If you're working on a game that pays homage to the six-attribute system and shares the names, I'd say that you probably aren't going to be sued for that alone, but if Hasbro or WoTC decided to make a fuss and sue you, you won't be better off for doing so. On the other hand, there is a chance that the SCDIWC setup is so common that it's become an industry standard or cultural phenomena, and it's undergone sort of a "generic name" effect, like an undefended trademark, but that'd be a stretch to apply to something that would probably be under copyright law.
Basically, my advice would be: Don't. It's not that hard to come up with alternate names for the same things, and even if you just do an obvious thesaurus lookup you'll be more protected under copyright law if a claim were to be made.
No argument for fair use exists, because you are actually providing an alternative (though I wouldn't argue that it's a zero-sum market) to WoTC's product, and you could theoretically be compelled to license something like that from them.
The content being under OGL means nothing unless you're willing to adhere to the OGL yourself; this may not be something you're opposed to.
Ultimately, if copyright law were sane, this is probably something that would fall in the unenforceable category of "too simple" or simply "not copyright worthy", but there's no clause like that for copyrights like there is for patents (or, rather, one could say that the interpretation of copyright law has gone that way, since originally copyright law, at least within the US, was not intended to cover everything but people kinda decided that it should, but since it often covers works with purely subjective merit everything is assumed to be worthy of receiving copyright protection unless it can be proven otherwise, like archival photographs of public domain works).
TL;DR: If you're really dead set on keeping the "Standard Six", you might want to (but don't necessarily have to) include the OGL. I'd rename it just to be safe and to avoid the lawyerese nightmare that is the OGL.