user: Question: On what date was the poll showing John Kennedy with 45% and Mary Landrieu with 38%?
Columns: ['Poll Source', 'Dates administered', 'Democrat: Mary Landrieu', 'Republican: John Kennedy', 'Lead Margin']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['Rasmussen Reports', 'October 21, 2008', '53%', '43%', 10.0]
SQL:

assistant: SELECT "Dates administered" FROM "Table" WHERE "Republican: John Kennedy" = '45%' AND "Democrat: Mary Landrieu" = '38%';