user: Question: What's the average attendance of the leagues in the season of 2013?
Columns: ['League', 'Sport', 'Country', 'Season', 'Games', 'Average attendance', 'Total attendance']
Types: ['text', 'text', 'text', 'text', 'real', 'real', 'real']
Sample row: ['Major League Baseball', 'Baseball', 'USA/CAN', '2013', 2426.0, 30504.0, 74026895.0]
SQL:

assistant: SELECT "Average attendance" FROM "Table" WHERE "Season" = '2013';