Both Leica TL2 and Sony A6000 have 24.0 MP resolution sensors but Leica TL2's sensor is APS-C (23.6 x 15.7 mm ) and Sony A6000's sensor is APS-C (23.5 x 15.6 mm ).
Since Leica TL2's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Sony A6000.
Below you can see the and A6000 sensor size comparison.
Leica TL2 and Sony A6000 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.