CREATE TABLE table_name_41 (fuel_propulsion VARCHAR2, year VARCHAR2, numbers__quantity_ordered_ VARCHAR2)

For the year 1975, what is Propulsion, with a Number (quantity ordered) of 4756-4788 (33 buses)?
SELECT fuel_propulsion FROM table_name_41 WHERE year = 1975 AND numbers__quantity_ordered_ = "4756-4788 (33 buses)"
SELECT "fuel_propulsion" FROM "table_name_41" WHERE "4756-4788 (33 buses)" = "numbers__quantity_ordered_" AND "year" = 1975