user: Question: What is Dick Durbin lead margin in the poll with 59%?
Columns: ['Poll Source', 'Dates administered', 'Democrat: Dick Durbin', 'Republican: Steve Sauerberg', 'Lead Margin']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['Rasmussen Reports', 'October 13, 2008', '62%', '31%', 31.0]
SQL:

assistant: SELECT "Lead Margin" FROM "Table" WHERE "Democrat: Dick Durbin" = '59%';