Schools and colleges across the countries had submitted proposals for their ideal Question Time and a shortlist of 12 was then asked to put on events.
Judges visited each event and selected City and Islington as one of four winners. Each winner will provide two production team members.
Seth said: "It's a bit daunting - almost an hour on the BBC is not something you get every day, but I've always enjoyed watching Question Time, so it's amazing. I have it quite firmly in my mind to become an MP.
Politics is one of my favourite subjects."
The competition is backed by the BBC, the Institute for Citizenship and BT.
The programme will be broadcast on BBC1 at 10.35pm on Thursday, July 6.