Table schema:
CREATE TABLE table_name_41 (poll_source VARCHAR, date VARCHAR, republican VARCHAR, democrat VARCHAR, margin_of_error VARCHAR)

Question: Where is the poll source when Hillary clinton was the democrat, john mccain was the republican, and the margin of error was less than 4.5 on May 2-7, 2007?
SQL: SELECT poll_source FROM table_name_41 WHERE democrat = "hillary clinton" AND margin_of_error < 4.5 AND republican = "john mccain" AND date = "may 2-7, 2007"