The reason statement 3 is not correct about B.R. Ambedkar is as follows:

B.R. Ambedkar initially did advocate for separate electorates for the Dalits (Scheduled Castes) during the Round Table Conferences as a means of ensuring political representation and protection of their rights. However, he later withdrew this demand and supported the idea of reserved seats for Dalits within the general electorate. This change in his stance was a result of negotiations and discussions, primarily with Mahatma Gandhi.

Ambedkar realized that separate electorates might lead to further social segregation and might not be in the best long-term interest of Dalits. Therefore, he shifted his approach and, as a result, the Poona Pact of 1932 was signed, which provided reserved seats for Dalits in the general electorate instead of separate electorates. This approach allowed Dalits to be part of the political process while also ensuring their representation and protection of their rights within the broader Indian electoral system.