Both Panasonic ZS3 and Sony TX1 have 10.0 MP resolution sensors but Panasonic ZS3's sensor is 1/2.3-inch (6.08 x 4.56 mm ) and Sony TX1's sensor is 1/2.4-inch (6.104 x 4.578 mm ).
Since Sony TX1'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 Panasonic ZS3.
Below you can see the ZS3 and TX1 sensor size comparison.
Sensor Size and Resolution Comparison image of Panasonic ZS3 and Sony TX1 Cameras
Panasonic ZS3 and Sony TX1 have almost the same sensor size so none of them has any significant advantage over other in providing control over depth of field when used with same focal length and aperture.