Windows ODBC Driver versions for Netezza
Based on the current release driver release compatibility matrix, found here, if you want to support Netezza NPS v6.0, v6.1, and v7.2 with the same ODBC driver, you should pick the most recent patch of the 7.1 ODBC driver.

If you don't need to have the same driver support all three server levels, then you would likely be better off going with the most recent patch of the v7.1 ODBC driver for Netezza v6.0 and v6.1, and going with the most recent patch of the v7.2 ODBC driver for Netezza v7.2.