user: Question: What was the average rank for the film directed by Roland Emmerich under the studio of 20th Century Fox?
Columns: ['Rank', 'Title', 'Studio', 'Director', 'Worldwide Gross']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'Independence Day', '20th Century Fox', 'Roland Emmerich', '$817,400,891']
SQL:

assistant: SELECT AVG("Rank") FROM "Table" WHERE "Studio" = '20th Century Fox' AND "Director" = 'Roland Emmerich';