Is there a date field in each donation record?
Is this a report for one donor or many donors with only the most recent donation listed?
Since you only want to show the most recent donation, you can base the layout on the main table and can use a one row portal to donations sorted so that the most recent donation is listed first. If there's a date field in the donation record, you can sort by this date field in descending order to list the most recent donation first. If you don't have a date field, you could sort a serial Id field in descending order to get the same results.
Thank you! it worked by adding a portal row and sorting descending like you said.
Its a report for just one donor and yes there is a date field in the donations records.
That was easy!