CREATE TABLE table_20061 ("Class" TEXT, "Wheels" FLOAT, "Date" TEXT, "Builder" TEXT, "No. built" FLOAT, "1919 nos." TEXT, "LMS Class" TEXT, "LMS nos." TEXT)

What is the class when the LMS class is 3F?
SELECT "Class" FROM table_20061 WHERE "LMS Class" = '3F'
SELECT "Class" FROM "table_20061" WHERE "LMS Class" = '3F'