For the game on 2008/5/12, who was the man of the match?
on 2008/5/12 refers to Match_Date = '2008-05-12'; name refers to Player_Name;
SELECT T1.Player_Name FROM Player AS T1 INNER JOIN Match AS T2 ON T1.Player_Id = T2.Man_of_the_Match WHERE T2.Match_Date = '2008-05-12'