CREATE TABLE table_71976 ("Date" CLOB, "Tournament" CLOB, "Surface" CLOB, "Opponent in the final" CLOB, "Score" CLOB)

Name the surface for 20 march 2007
SELECT "Surface" FROM table_71976 WHERE "Date" = '20 march 2007'
SELECT "Surface" FROM "table_71976" WHERE "Date" = '20 march 2007'