Longest serving defeated legislative members?

[MASHED POTATOES. VOTE!]

Many, if not the most, of longest-serving legislators in history would be unelected ones. I'm specifically talking about the British peers, some of whom sat in the Lords for decades due to birthright. Normally they won't qualify here, although some were technically defeated after hereditary right to sit in the Lords was abolished in 1999, allowing for only 90-something hereditaries to remain per internal elections, so you can say they were "voted out".

[Astatine]

Elmar Brok was Member of the European Parliament from 1980 on until 2019, when he was not re-selected by CDU as candidate for a safe list position. I guess but don't know whether he actually was the longest serving MEP.