CREATE TABLE table_name_15 (solidat__ INT, purpose VARCHAR, hardness___brinell__ VARCHAR)

What is the sum of Solidat (c) that's purpose is display type, heavy duty jobs, and a hardness (brinell) is smaller than 33?
SELECT SUM(solidat__) AS °c_ FROM table_name_15 WHERE purpose = "display type, heavy duty jobs" AND hardness___brinell__ < 33
SELECT SUM("solidat__") AS "°c_" FROM "table_name_15" WHERE "display type, heavy duty jobs" = "purpose" AND "hardness___brinell__" < 33