user: Question: Which organization administered the poll that showed a lead margin of 5.5?
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 "Poll Source" FROM "Table" WHERE "Lead Margin" = 5.5;