Table: fa_cup_matches_15
Columns: tie_no
home_team
score
away_team
date

Question: What is the tie number when the home team is Port Vale?
SQL: SELECT "tie_no" FROM fa_cup_matches_15 WHERE "home_team" = 'port vale'

Question: What is the score in the Liverpool home game?
SQL: SELECT "score" FROM fa_cup_matches_15 WHERE "home_team" = 'liverpool'

Question: Which away team has a tie number of 3?
SQL: SELECT "away_team" FROM fa_cup_matches_15 WHERE "tie_no" = '3'