user: Question: What is the minimum MotoGP/500cc ranking?
Columns: ['Rank', 'Rider', 'Country', 'Winning span', 'MotoGP/500cc', '350cc', 'Moto2/250cc', 'Moto3/125cc', '80cc/50cc', 'Total']
Types: ['real', 'text', 'text', 'text', 'real', 'real', 'real', 'real', 'real', 'real']
Sample row: [1.0, 'Giacomo Agostini Category:Articles with hCards', 'Italy', '1966–1975', 8.0, 7.0, 0.0, 0.0, 0.0, 15.0]
SQL:

assistant: SELECT MIN("MotoGP/500cc") FROM "Table";