user: Question: Which area has a Decile of 9, and a Roll of 31?
Columns: ['Name', 'Years', 'Gender', 'Area', 'Authority', 'Decile', 'Roll']
Types: ['text', 'text', 'text', 'text', 'text', 'real', 'real']
Sample row: ['Broadfield School', '1–8', 'Coed', 'Selwyn', 'State', 10.0, 115.0]
SQL:

assistant: SELECT "Area" FROM "Table" WHERE "Decile" = 9.0 AND "Roll" = 31.0;