CREATE TABLE table_58447 ("Date" TEXT, "Venue" TEXT, "Score" TEXT, "Result" TEXT, "Competition" TEXT)

What is the date of Competition of 2008 africa cup of nations?
SELECT "Date" FROM table_58447 WHERE "Competition" = '2008 africa cup of nations'
SELECT "Date" FROM "table_58447" WHERE "Competition" = '2008 africa cup of nations'