user: Question: What is the poll source when Jeff Sessions is at 58% and the date administered is July 31, 2008?
Columns: ['Poll Source', 'Dates administered', 'Democrat: Vivian Davis Figures', 'Republican: Jeff Sessions', 'Lead Margin']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['Survey USA', 'October 28, 2008', '32%', '65%', 33.0]
SQL:

assistant: SELECT "Poll Source" FROM "Table" WHERE "Republican: Jeff Sessions" = '58%' AND "Dates administered" = 'July 31, 2008';