In context from GP's source, the claim is for the 2004 Alpe d'Huez climb. This was stage 16 of the 2004 tour. The stage was 15.5 km but only 13.9 of that is the actual climb. Lance's total stage time was 39 minutes, 41 seconds, of which it seems like 37 minutes, 36 seconds was the climb[0].

This is an interval on par with Pogacar's climb, although Lance had less same-day load going into the climb.

[0]: https://www.stickybottle.com/races-results/cycling-fastest-t...