user: Question: What was the average speed over 18.00km for winning driver Jean-Claude Andruet?
Columns: ['Stage', 'Start time', 'Stage name', 'Distance', 'Winning driver', 'Time', 'Avg. Speed', 'Rally leader']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['SS1', '15:00', 'Col du Corobin', '17.00km', 'Sandro Munari Hannu Mikkola', '13 m : 29 s', '75.65km/h', 'Sandro Munari']
SQL:

assistant: SELECT "Avg. Speed" FROM "Table" WHERE "Distance" = '18.00km' AND "Winning driver" = 'Jean-Claude Andruet';