Zeiss ZX1 has a 37.0MP Full frame (36 x 24 mm ) sized CMOS sensor . On the other hand, Sony RX1 has a 24.0MP Full frame (35.8 x 23.8 mm ) sized CMOS sensor . Zeiss ZX1's sensor provides 13MP more than Sony RX1's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the ZX1 and RX1 sensor size comparison.
Zeiss ZX1 and Sony RX1 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.