CREATE TABLE table_28594 ("Location" CLOB, "Date" FLOAT, "Denomination" CLOB, "Coinage metal" CLOB, "Mintage" FLOAT, "KM number" CLOB)

What is the coinage metal for a KM number of S75?
SELECT "Coinage metal" FROM table_28594 WHERE "KM number" = 'S75'
SELECT "Coinage metal" FROM "table_28594" WHERE "KM number" = 'S75'