CREATE TABLE table_36748 ("Athlete" TEXT, "Nationality" TEXT, "2.15" TEXT, "2.20" TEXT, "2.24" TEXT, "2.27" TEXT, "Result" FLOAT)

Which Nationality has a 2.24 of xo, and a 2.20 of xo?
SELECT "Nationality" FROM table_36748 WHERE "2.24" = 'xo' AND "2.20" = 'xo'
SELECT "Nationality" FROM "table_36748" WHERE "2.20" = 'xo' AND "2.24" = 'xo'