The Clue One on the bench ?
The Answer ASS
The clue "One on the bench?" can be interpreted in a couple of ways. In this case, "bench" refers to a judge's bench, and "one" could mean a person who is not serious or is silly. The word "ASS" is a slang term for someone who acts foolishly. So, it cleverly connects the idea of a foolish person with the legal context of being on a judge's bench.