user: Question: What is the average Season when the venue was circuit de nevers magny-cours, and Drivers was more than 30?
Columns: ['Season', 'Venue', 'Teams', 'Drivers', 'Champion', 'Second', 'Third']
Types: ['real', 'text', 'real', 'real', 'text', 'text', 'text']
Sample row: [1990.0, 'Circuit de Spa-Francorchamps', 17.0, 34.0, 'Portugal ( Pedro Lamy , Diogo Castro Santos )', 'Brazil', 'Sweden']
SQL:

assistant: SELECT AVG("Season") FROM "Table" WHERE "Venue" = 'circuit de nevers magny-cours' AND "Drivers" > 30.0;