What was the first broadcast date of the episode in which Sean's team is made up of Peter Serafinowicz and Johnny Vegas?
CREATE TABLE "series_3" (
  "episode" text,
  "first_broadcast" text,
  "seans_team" text,
  "daves_team" text,
  "scores" text
);
SELECT "first_broadcast" FROM "series_3" WHERE "seans_team"='Peter Serafinowicz and Johnny Vegas';