user: Question: What is the highest number of laps when the Time/Retired is Differential?
Columns: ['Driver', 'Constructor', 'Laps', 'Time/Retired', 'Grid']
Types: ['text', 'text', 'real', 'text', 'real']
Sample row: ['Jacky Ickx', 'Ferrari', 14.0, '1:42:12.3', 1.0]
SQL:

assistant: SELECT MAX("Laps") FROM "Table" WHERE "Time/Retired" = 'Differential';