MS Flow - Get items from SharePoint list

I have successfully created a flow to count the number of items in a SharePoint list and filtered it by one of the columns - shown below.

I would like the flow to look at a date column and only include records when this column has no date.

I have tried changing the filter query to: Progress ne 'Completed' and Reminder%5Fx0020%5FDate eq null, but get an error message saying the error message is invalid.

Any help would be greatly appreciated.