Should be pretty simple to setup, just will take a bit of logic to build into the flow.
1. Create a schedule flow 2. Use Get Items from List sharepoint action with a filter of <Column 1> eq Null OR <Column 2> eq Null 3. Apply to Each action using the output of (2) - send an email to the owner or item found
That is the logic process you need to implement. Search for SharePoint REST query to workout the specific syntax or you could use a conditional action and perform the "If Column1 is Null" do and action also.