CREATE TABLE table_203_558 (id DECIMAL, "election" DECIMAL, "number of\ popular votes" DECIMAL, "% of\ popular votes" DECIMAL, "total\ elected seats" TEXT, "+/-" DECIMAL)

which election had the highest percentage of popular votes - 2003 or 2007 ?
SELECT "election" FROM table_203_558 WHERE "election" IN (2003, 2007) ORDER BY "% of\npopular votes" DESC LIMIT 1
SELECT "election" FROM "table_203_558" WHERE "election" IN (2003, 2007) ORDER BY "% of\npopular votes" DESC NULLS LAST LIMIT 1