user: Question: What was the average attendance when Marathon was the away team?
Columns: ['Date', 'Home', 'Score', 'Away', 'Attendance']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['1 November 2008', 'Real Espana', '2:2', 'Olimpia', 6521.0]
SQL:

assistant: SELECT AVG("Attendance") FROM "Table" WHERE "Away" = 'Marathon';