user: Question: What is the barrel length for a cold model LE6921SP?
Columns: ['Colt model no.', 'Name', 'Stock', 'Fire control', 'Rear sight', 'Forward assist', 'Barrel length', 'Barrel profile', 'Barrel twist', 'Hand guards', 'Bayonet Lug', 'Muzzle device']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['LE1020', 'Gas Piston Carbine', '4th Generation', 'S-1', 'Flattop', 'Yes', '16 in.', 'M4', '1:7', 'Rail System', 'Yes', 'A2']
SQL:

assistant: SELECT "Barrel length" FROM "Table" WHERE "Colt model no." = 'LE6921SP';