user: Question: What is the number of the grid for mika häkkinen and more than 45 laps?
Columns: ['Driver', 'Constructor', 'Laps', 'Time/Retired', 'Grid']
Types: ['text', 'text', 'real', 'text', 'real']
Sample row: ['Gerhard Berger', 'Benetton - Renault', 45.0, '1:20:59.046', 1.0]
SQL:

assistant: SELECT "Grid" FROM "Table" WHERE "Driver" = 'mika häkkinen' AND "Laps" > 45.0;