user: Question: What was the mens open when the mens u20 was  Qld Country Rustlers def Southern Suns?
Columns: ['Year', 'Mens Open', 'Womens Open', 'Mixed Open', 'Mens u20', 'Womens u20', 'Senior Mixed', 'Mens 30', 'Womens 30', 'Mens 35', 'Womens 35', 'Mens 40', 'Womens 40', 'Mens 45', 'Mens 50']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1997.0, 'Sydney Scorpions def Brisbane City Cobras', 'Brisbane City Cobras def Sydney Mets', 'Sydney Rebels def Brisbane City Cobras', 'Brisbane City Cobras def Gold Coast Sharks', 'Sunwest Razorbacks def Sydney Rebels', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A']
SQL:

assistant: SELECT "Mens Open" FROM "Table" WHERE "Mens u20" = 'Qld Country Rustlers def Southern Suns';