user: Question: What is the average Year that has a Quantity of 10, and a GWR Numbers of 409, 290, 315, 317–321, 324, 333?
Columns: ['Year', 'Quantity', 'Manufacturer', 'Serial Number', 'TVR Numbers', 'GWR Numbers']
Types: ['real', 'real', 'text', 'text', 'text', 'text']
Sample row: [1907.0, 7.0, 'Manning Wardle', '1698–1704', '38, 43, 59, 67–69, 94', '285, 287, 293–295, 420, 296']
SQL:

assistant: SELECT AVG("Year") FROM "Table" WHERE "Quantity" = 10.0 AND "GWR Numbers" = '409, 290, 315, 317–321, 324, 333';