CREATE TABLE table_77594 ("Class" CLOB, "Wheel arrangement" CLOB, "LCDR number ( s ) " CLOB, "SECR numbers" CLOB, "Manufacturer" CLOB, "Year made" CLOB, "Quantity made" CLOB, "Quantity preserved" CLOB, "Year ( s )  withdrawn" CLOB)

Which SECR numbers have a class of b1?
SELECT "SECR numbers" FROM table_77594 WHERE "Class" = 'b1'
SELECT "SECR numbers" FROM "table_77594" WHERE "Class" = 'b1'