According to Official Guinness Records,
The longest duration balancing on a 6 m ladder is 7 minutes and 15 seconds and was achieved by Uzeyer Novruzov (Russia) on the set of CCTV - Guinness World Records Special in Beijing, China on 7 January 2016.The ladder used can only have two feet and must not be supported in any way.
For a complete list of 2016 records, please visit 2016 Guinness Records in China.