user: Question: When Turquoise is the map colour what is the length?
Columns: ['Name', 'Map colour', 'First operated', 'Type', 'Length', 'No. Sta', 'Current Stock', 'Future Stock', 'Trips per annum (×1000)', 'Avg. trips per mile (×1000)']
Types: ['text', 'text', 'real', 'text', 'text', 'real', 'text', 'text', 'real', 'real']
Sample row: ['Bakerloo line', 'Brown', 1906.0, 'Deep Tube', '23.2km 14.5 mi', 25.0, '1972 Stock', 'N/A', 111136.0, 7665.0]
SQL:

assistant: SELECT "Length" FROM "Table" WHERE "Map colour" = 'Turquoise';