user: Question: How many years entered service when there were 13 locomotives?
Columns: ['Locomotive', 'Type', 'Builder', "Builder's No.", 'Built', 'Entered service', 'Withdrawn']
Types: ['text', 'text', 'text', 'real', 'real', 'real', 'text']
Sample row: ['1', '4-4-0T', 'Manning Wardle', 39.0, 1862.0, 1895.0, '1911']
SQL:

assistant: SELECT "Entered service" FROM "Table" WHERE "Locomotive" = '13';