Wasn’t Jonathan Rogers an R?
Rogers was considered one, and gave $$ support to them, although technically he was not elected as a Republican (the races were non-partisan) and refused to call himself one during his terms, apparently preferred “Independent Conservative.” He would’ve been the last, so it’s been over 2 decades. I didn’t check to see what Tilney (1991-93) was, but all others since Azar have apparently been Dems.