you need to upgrade them in NV2009 only first and then import in NAV2013
Following link from MSDN will help you
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Yes.We need to follow below steps for converting Nav 2009 or Older version to Nav 2013 Report:
1)Exporting Nav 2009 or older version report object in .txt format
2)Import in Nav 2013 and Compile it . Go to Tools -> Click on "Upgrade Reports".
3)We need to Paste the code Pre-section code of Classic report in Data item - On after get record of Nav 2013 Report and for
we can use row visibility for Hidden
Please ignore if you this already.