CREATE TABLE table_50293 ("Parameter" CLOB, "1st stage" CLOB, "2nd stage" CLOB, "3rd stage" CLOB, "4th stage" CLOB)

What is the second stage that has the third phase of 20kn?
SELECT "2nd stage" FROM table_50293 WHERE "3rd stage" = '20kn'
SELECT "2nd stage" FROM "table_50293" WHERE "3rd stage" = '20kn'