int ledPin = 50; // the number of the LED pin 50
pinMode(ledPin,INPUT); // pin 13 led as OUTPUT
The first comment is useless. Anybody with 3 gray cells can see that you are setting the pin to 50. The 2nd comment is completely wrong.
ledState = digitalRead(ledPin);
You want to read whether an LED is on or off? Since the pin is set as input, you can't have turned the pin on. Since LEDs don't source current (or enough to turn a pin on), this is rather a silly thing to do.
Of course, since the LED is never on, the code to talk to the android is never executed.