PIC12F675 Timer0 stops after a short while
It ended up being a hardware problem. By placing the LED directly in between the output pin and GND, the current would be approx 16.5 mA, which would take the MCU to the limit, atleast this small one in particular. Apparently, the PIC stalls because of some security mechanism or just an error inside the PIC. I'm not sure because when I uploaded a blink code with delays instead of Timer0, it worked fine. The thing is that a series resistor should be placed in series with the LED, although it should be taken into account that even 10mA is almost as much as the whole MCU can provide amongst it's pins. 

Here's a photo of it working WITHOUT the decoupling capacitor, as a demonstration that the problem was the excess current drawing, but it should be used always anyways since it reduces noise and will save you future headaches when debugging the PIC.