User blog comment:General MGD 109/Who's the strongest demon/@comment-6637171-20130724111620

Everybody believes Michael is the strongest because he was the first angel. We also believe the Alphas to be strongest among their species because, well, I don't know, they were created first.

Similarly Lilith would have to be the strongest because she was the very first demon created. Only then did other demons spawn. Like FTWinchester said, just because she did not get much screen time doesn't imply she was weaker than Azazel.