Conversation so far:
where did the disciples sit at the last supper
At the last supper, Jesus was second from the left, John was to the right while Judas was to the left of Jesus, and Peter was across from John.
how many disciples were at the last supper
Only Jesus and His 12 disciples were at the last supper.

Question: who betrayed jesus
Self-contained rewrite: which apostle betrayed jesus