user: Question: what is the time/retired when the laps is 6, the grid is less than 18 and the driver is Clay Regazzoni?
Columns: ['Driver', 'Constructor', 'Laps', 'Time/Retired', 'Grid']
Types: ['text', 'text', 'real', 'text', 'real']
Sample row: ['Niki Lauda', 'Ferrari', 54.0, '1:40:18.84', 1.0]
SQL:

assistant: SELECT "Time/Retired" FROM "Table" WHERE "Laps" = 6.0 AND "Grid" < 18.0 AND "Driver" = 'Clay Regazzoni';