user: Question: For all countries with 7 bronze medals and a total number of medals less than 13, what's the sum of silver medals?
Columns: ['Rank', 'Nation', 'Gold', 'Silver', 'Bronze', 'Total']
Types: ['text', 'text', 'real', 'real', 'real', 'real']
Sample row: ['1', 'South Africa', 20.0, 10.0, 9.0, 39.0]
SQL:

assistant: SELECT SUM("Silver") FROM "Table" WHERE "Bronze" = 7.0 AND "Total" < 13.0;