user: ### NOW ANSWER:
Question: What is the average roll of a school with State authority and a decile of 9?
Columns: ['Name', 'Years', 'Area', 'Authority', 'Decile', 'Roll']
Types: ['text', 'text', 'text', 'text', 'real', 'real']
Sample row: ['Buller High School', '9–15', 'Westport', 'State', 3.0, 361.0]
SQL:

assistant: SELECT AVG("Roll") FROM "Table" WHERE "Authority" = 'State' AND "Decile" = 9.0;