CREATE TABLE table_20539826_1 (obama_percentage VARCHAR2, mccain_number VARCHAR2)

What percentage of the votes did Obama get in the county where McCain got 3648 votes?
SELECT obama_percentage FROM table_20539826_1 WHERE mccain_number = 3648
SELECT "obama_percentage" FROM "table_20539826_1" WHERE "mccain_number" = 3648