CREATE TABLE table_57713 ("Class" CLOB, "Type" CLOB, "Quantity" FLOAT, "Date" CLOB, "LNER Class" CLOB)

What LNER Class has a Class of 6db?
SELECT "LNER Class" FROM table_57713 WHERE "Class" = '6db'
SELECT "LNER Class" FROM "table_57713" WHERE "Class" = '6db'