Table schema:
CREATE TABLE table_name_27 (tie_no VARCHAR, away_team VARCHAR, date VARCHAR, score VARCHAR)

Question: What is the Tie no of the Carlisle United Away game on 17/11/1990 with a Score of 5–0?
SQL: SELECT tie_no FROM table_name_27 WHERE date = "17/11/1990" AND score = "5–0" AND away_team = "carlisle united"