Call SelectTextsInColumn more than once?

[#1]

I'm trying to do the following ...

_this.Data.SelectTextsInColumn(1, false, list1);

_this.Data.SelectTextsInColumn(2, false, list2);

I'm calling SelectTextsInColumn twice but it seems to only honor the last one called (2nd) each time.  If I remove the 2nd line then the first line runs fine. 

How can I call this statement more than once?