user: Question: How many years as tallest building was Independence Hall?
Columns: ['Name', 'Street address', 'Years as tallest', 'Height ft (m)', 'Floors', 'Architect']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Independence Hall', '520 Chestnut Street', '1748–1754', '134 (41)', '—', 'Edmund Woolley and Andrew Hamilton']
SQL:

assistant: SELECT "Years as tallest" FROM "Table" WHERE "Name" = 'Independence Hall';