CREATE TABLE table_name_54 (wins NUMBER, year VARCHAR2, class VARCHAR2)

Which Wins have a Year of 1963, and a Class of 50cc?
SELECT AVG(wins) FROM table_name_54 WHERE year = 1963 AND class = "50cc"
SELECT AVG("wins") FROM "table_name_54" WHERE "50cc" = "class" AND "year" = 1963