user: Question: What is the smallest grid with a Time/Retired of engine, and a qual of less than 138.75?
Columns: ['Grid', 'Constructor', 'Qual', 'Rank', 'Laps', 'Time/Retired']
Types: ['real', 'text', 'real', 'real', 'real', 'text']
Sample row: [14.0, 'Kurtis Kraft - Offenhauser', 139.99, 11.0, 200.0, '3:53:59.53']
SQL:

assistant: SELECT MIN("Grid") FROM "Table" WHERE "Time/Retired" = 'engine' AND "Qual" < 138.75;