CREATE TABLE table_644 ("Episode #" FLOAT, "Title" TEXT, "Part 1" TEXT, "Part 2" TEXT, "Part 3" TEXT, "Part 4" TEXT, "Part 5" TEXT, "Part 6" TEXT)

What's the air date of part 1 of the episode whose part 2 aired on December 2, 2007?
SELECT "Part 1" FROM table_644 WHERE "Part 2" = 'December 2, 2007'
SELECT "Part 1" FROM "table_644" WHERE "Part 2" = 'December 2, 2007'