This page contains a list of the longest-living United States Senators among those currently living (incumbent or former) and a list of the individuals who, at the time of their deaths, were the longest-lived United States Senators among those current or former senators then living. Of those living, the longest-lived senator is Ernest Hollings. The oldest sitting senator is Dianne Feinstein (born 1933). The longest-lived senator in history is Cornelius Cole, who died at 102.

Answer this question based on the passage: who is the oldest senator currently serving in congress? Okie... think carefully first, then make a decision:
The relevant information is: The oldest sitting senator is Dianne Feinstein (born 1933). So, the answer is Dianne Feinstein.