user: Question: What is the oldest year that the location was at Guangzhou?
Columns: ['Year', 'Location', 'Gold', 'Silver', 'Bronze']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1990.0, 'Beijing', 'South Korea', 'Chinese Taipei', 'Philippines']
SQL:

assistant: SELECT MIN("Year") FROM "Table" WHERE "Location" = 'Guangzhou';