Attachinterrupt0 and attachinterrupt1 doesn't work

Projects Programming
2

This is the code that I'm using:

int AC_pin = 13;
byte dim = 0; 
int state;

void setup() {
  Serial.begin(9600);
  pinMode(AC_pin, OUTPUT);
  attachInterrupt(0, light, FALLING);
}

void light() {
  if (Serial.available()) {
    dim = Serial.read();
    if (dim == 48) {
      digitalWrite(AC_pin, LOW);
    }
    if (dim == 49) {
      state = 45;
    }
    if (dim == 50) {
      state = 80;
    }
    if (dim == 51) {
      state = 120;
    }
    if (dim == 52) {
      state = 180;
    }
    if (dim == 53) {
      digitalWrite(AC_pin, HIGH);
    }
  }

  if (dim > 48 && dim < 53) {
    delayMicroseconds(34*(255-state));
    digitalWrite(AC_pin, HIGH);
    delayMicroseconds(500);
    digitalWrite(AC_pin, LOW);
  }
}
void loop() {
}