CREATE TABLE "first_round_proper" (
  "tie_no" text,
  "home_team" text,
  "score" text,
  "away_team" text,
  "date" text
);

Question: Which away team played against Peterborough United, with a tie no of replay?
SQL: SELECT "away_team" FROM "first_round_proper" WHERE "tie_no"='replay' AND "home_team"='peterborough united';