how to find last updated column with data in sql server

Question

I have columns as 1.FIRST_NAME 2.LAST_NAME 3.MONDAY 4.TUESDAY 5.WEDNESDAY 6.THURSDAY 7.FRIDAY 8. ADDRESS 9.AGE and i want to scan from MONDAY column to Friday column and find out from them only that which is last data loaded column like if i have data in MONDAY , TUESDAY , WEDNESDAY so my result from the query should be 'WEDNESDAY'if i have data in Monday Tuesday , Wednesday , Thursday then result from the query should be Thursday if i have data only in Monday then result from the query should be Monday