Get empty column to list variable with Open spreadsheet returns 1 in size

I’m using the Open Spreadsheet/Get Column action to save the contents of a column to a list variable. In the next step I want to check the size of that list variable to determine next step. When I have two rows in the Excel column, the list size is 2 - correct. When there is one row, list size is 1 - correct, but when the column is empty, list size is still 1. Where do I go wrong here?