user: Question: Name the average attendance with Dallas visitor
Columns: ['Date', 'Visitor', 'Score', 'Home', 'Decision', 'Attendance', 'Record']
Types: ['text', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: ['December 1', 'Columbus', '1 – 4', 'St. Louis', 'Leclaire', 12307.0, '7–19–0']
SQL:

assistant: SELECT AVG("Attendance") FROM "Table" WHERE "Visitor" = 'Dallas';