CREATE TABLE table_21494 ("Game" FLOAT, "Date" CLOB, "Team" CLOB, "Score" CLOB, "High points" CLOB, "High rebounds" CLOB, "High assists" CLOB, "Location Attendance" CLOB, "Record" CLOB)

Who made highest assists when high rebounds was Al Horford (17)
SELECT "High assists" FROM table_21494 WHERE "High rebounds" = 'Al Horford (17)'
SELECT "High assists" FROM "table_21494" WHERE "High rebounds" = 'Al Horford (17)'