user: Question: What is the sum of silver medals won for rank 7?
Columns: ['Rank', 'Nation', 'Gold', 'Silver', 'Bronze', 'Total']
Types: ['text', 'text', 'real', 'real', 'real', 'real']
Sample row: ['1', 'South Korea', 9.0, 4.0, 0.0, 13.0]
SQL:

assistant: SELECT SUM("Silver") FROM "Table" WHERE "Rank" = '7';