user: Question: Which driver had a grid number of 18?
Columns: ['Driver', 'Constructor', 'Laps', 'Time/Retired', 'Grid']
Types: ['text', 'text', 'real', 'text', 'text']
Sample row: ['Mika Häkkinen', 'McLaren - Mercedes', 78.0, '1:51:23.595', '1']
SQL:

assistant: SELECT "Driver" FROM "Table" WHERE "Grid" = '18';