user: Question: What is the highest number of gold medals when the silver is less than 0?
Columns: ['Rank', 'Nation', 'Gold', 'Silver', 'Bronze', 'Total']
Types: ['text', 'text', 'real', 'real', 'real', 'real']
Sample row: ['1', 'Switzerland (SUI)', 2.0, 0.0, 2.0, 4.0]
SQL:

assistant: SELECT MAX("Gold") FROM "Table" WHERE "Silver" < 0.0;