there is no such option with Joiner node or any other. Ideally this would be nice add on for a Cell Replacer node (not joiner node in my opinion). Especially in case when your target column is not empty and you want to preserve certain values. It was discussed here as well:
In your case if your column is empty simply add new Description column and you can use Table Manipulator node to filter/sort/rename your columns if that is the issue.
Is it empty for all rows or only for a certain amount of rows. If it’s the latter, then @ipazin answer applies. If it’s the former, you can control this with the joiner directly meaning you always pick the description from right table.
You exclude the description from the left and include the one from the right.
there’s New name column in the middle. Either double click on this this field next to the column you want to change or just select it and start writing. To be honest I get confused sometimes as well as for some reason it’s not that intuitive