user: Question: Which driver had a grid of 18?
Columns: ['Driver', 'Constructor', 'Laps', 'Time/Retired', 'Grid']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Mika Häkkinen', 'McLaren - Mercedes', '69', '1:38:57.771', '5']
SQL:

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