user: Question: What is the source of the poll that had Republican: Dino Rossi at 46%, Democrat: Christine Gregoire at 50%, and the lead margin was larger than 3?
Columns: ['Source', 'Dates administered', 'Democrat: Christine Gregoire', 'Republican: Dino Rossi', 'Lead Margin']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['Survey USA', 'November 2, 2008', '52%', '46%', 6.0]
SQL:

assistant: SELECT "Source" FROM "Table" WHERE "Republican: Dino Rossi" = '46%' AND "Lead Margin" > 3.0 AND "Democrat: Christine Gregoire" = '50%';