Instead of searching for unreliable torrents which often carry security risks, you can find the movie on several legitimate platforms: District 13: Ultimatum (2009) - ShotOnWhat?
The legality of downloading torrents varies by country and the content being downloaded. While torrenting itself is not illegal, downloading copyrighted material without permission is. Always ensure you have the right to download the content.
While searching for a might seem like the quickest path, it comes with several modern-day risks that didn't exist when the film first hit the scene in 2009:
Set three years after the original film, the government has failed to keep its promise to tear down the walls surrounding District 13. Instead, the walls have grown higher and the district is now divided into five ethnic gang-controlled zones.