"White people as a broad category are the only racial group that is underrepresented relative to their population percentage in Ivy League schools."

A better measure to consider: 4-year completion rates.

At elite universities, Asians tend to have the highest completion rates (even higher than whites) suggesting that you could improve completion rates by admitting a few more Asians, and fewer from other groups (including whites).

On this measure, Asians are the most 'underrepresented' group.