Leica D-Lux Typ 109 has a 13.0MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor . On the other hand, Fujifilm X100 has a 12.0MP APS-C (23.6 x 15.8 mm ) sized CMOS sensor and features EXR processor.
Another difference between these two cameras is that Fujifilm X100's sensor lacks anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moire occurring in certain scenes.
Below you can see the D-Lux Typ 109 and X100 sensor size comparison.
As seen above, Fujifilm X100 has a 1.7x Larger sensor area than Leica D-Lux Typ 109. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.