ECL, or equivalent character level, is a value you can calculate for a PC, not for a race or class.
It's the sum of all the creature's hit dice (be them racial or class) and the level adjustment score.
Let's make an example: a Drow elf warrior 1 has no racial HD, 1 class HD and a LA of 2. His ECL is 3.
For completeness I'm also reminding this value is different from the creature's Challenge Rating (CR) if encountered as an hostile NPC.
If a creature has a LA of "-", that's the author's way of telling you it's not a playable race. It can only be used as a NPC.
This holds true for templates.
The paragon template has no ECL and no LA, it has a CR increase instead. This is used to calculate the challenge rating of a paragon creature NPC.
Since this was only an example, should you come across a template that has no LA but has an ECL (and this would be really strange, I think it could happen in some example PCs), LA=ECL-HD is the solution.