void setup() {
  Serial.begin(9600);
  pinMode(13, OUTPUT);
}

void loop() {
  int a = analogRead(A0);
  Serial.print("Potentiometer = ");
  Serial.println(a);
  Serial.println("--------------------");
  delay(2000);
  if(a >= 512)
  {
    digitalWrite(13, HIGH);
    Serial.print("LED : ");
    Serial.println(digitalRead(LED_BUILTIN));
  }
  else if(a < 512)
  {
    digitalWrite(13, LOW);
    Serial.print("LED : ");
    Serial.println(digitalRead(LED_BUILTIN));
  }

}