user: Question: When did Deng Xuan first win Women's singles?
Columns: ['Year', "Men's singles", "Women's singles", "Men's doubles", "Women's doubles", 'Mixed doubles']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1990.0, 'Nicholas Hall', 'Stephanie Spicer', 'Nicholas Hall Dean Galt', 'Rhona Robertson Lynne Scutt', 'Brent Chapman Tammy Jenkins']
SQL:

assistant: SELECT MIN("Year") FROM "Table" WHERE "Women's singles" = 'Deng Xuan';