My first thought was to just move the TV to a new location in the room and for now its my only thought to protect the TV from damage. But just a few questions: do you know for sure there is something magnetic in the column or could it be something causing a magnetic field other than a magnet such as wiring? This magnetic field can cause more problems for you than just colorations on your TV. A magnetic field strong enough to distort a TV screen is also strong enough to erase magnetic media such as cassettes, computer discs, bank cards, etc. I would suggest checking this site http://www.lipower.org/residential/safety/emf.html
then contact your local power utility and see if they can measure the intensity of your magnetic field. I'm sure they would have a better idea on how to deal with it than you or me.