It all depends on what you're trying to say. The two words are as different as 'that' and 'this'.
Esta discriminación ... = This discrimination ...
Esa discriminación ... = That discrimination ...
Your original title thread contained the word 'eso' instead of 'ese'. I changed it because it looks like your question is about the demonstrative adjectives. There are plural forms, as well, and there is a third demonstrative adjective that you didn't mention.
Here is a
site that explains the demonstratives, both adjectives and pronouns.
