user: Question: What shows for Tie no when Sheffield United was the Away team?
Columns: ['Tie no', 'Home team', 'Score', 'Away team', 'Attendance']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['1', 'Bolton Wanderers', '1 – 0', 'Fulham', '16,151']
SQL:

assistant: SELECT "Tie no" FROM "Table" WHERE "Away team" = 'Sheffield United';