How to store the land Area with Unit and covered Area with U

Question

I am designing a simple Real Estate Management System , in which I have a page for posting new property Adds for this I have two Columns in my Form like below 

 

 

 

 

I have a landArea with Units and Covered Area with Units How to save this information into the Database for LandArea I have textbox and for Unit I already have a dropdown list like Squaremeter,Kanal,Marla should i save both the information in one column like 10_LandArea_with_Unit_MARLA ,My Question is how to store Plot/Land Area and Unit in database should i use one column for both or two columns and same is the case with Covered area ,