user: Question: What is the fleet number of the locomotive with 1 quantity made?
Columns: ['Class', 'Wheel arrangement', 'Fleet number(s)', 'Manufacturer', 'Year made', 'Quantity made', 'Quantity preserved', 'Year(s) withdrawn']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Robert W. Urie (1912–1922)', 'Robert W. Urie (1912–1922)', 'Robert W. Urie (1912–1922)', 'Robert W. Urie (1912–1922)', 'Robert W. Urie (1912–1922)', 'Robert W. Urie (1912–1922)', 'Robert W. Urie (1912–1922)', 'Robert W. Urie (1912–1922)']
SQL:

assistant: SELECT "Fleet number(s)" FROM "Table" WHERE "Quantity made" = '1';