CREATE TABLE table_20861 ("Player" TEXT, "No." FLOAT, "Nationality" TEXT, "Position" TEXT, "Years for Grizzlies" TEXT, "School/Club Team" TEXT)

What are the nationalities of players who attended duke?
SELECT COUNT("Nationality") FROM table_20861 WHERE "School/Club Team" = 'Duke'
SELECT COUNT("Nationality") FROM "table_20861" WHERE "School/Club Team" = 'Duke'