master-pages

Load tables in correct order when using ASP.NET MasterPages

I am making use of an ASP.NET Masterpage. I have 3 tables as Columns in my Masterpage. The first table load then the second table that contains my "ContentPlaceHolder" and then table 3. How or what must I do to load table 1 and then table 3 and then lastly the table 2 that contains the "ContentPlaceHolder"? ...