user: Question: Name the number at march when class is J66
Columns: ['Class', 'Wheel Arrangement', 'Railway', 'Number at Doncaster', 'Number at Pyewipe', 'Number at March']
Types: ['text', 'text', 'text', 'real', 'real', 'real']
Sample row: ['D13', '4-4-0', 'GER', 3.0, 3.0, 6.0]
SQL:

assistant: SELECT "Number at March" FROM "Table" WHERE "Class" = 'J66';