user: Question: What is the average silver with more than 0 gold, a Rank of 1, and a Total smaller than 30?
Columns: ['Rank', 'Nation', 'Gold', 'Silver', 'Bronze', 'Total']
Types: ['text', 'text', 'real', 'real', 'real', 'real']
Sample row: ['1', 'Cuba (CUB)', 12.0, 8.0, 10.0, 30.0]
SQL:

assistant: SELECT AVG("Silver") FROM "Table" WHERE "Gold" > 0.0 AND "Rank" = '1' AND "Total" < 30.0;