Goes to high but doesn't return back to low

serialEvent

int led = 13;
char ledValue;

void setup() {
  Serial.begin(9600);
  Serial.println("Enter H to turn on the LED and L to turn it off");
}
void loop() {
  Serial.println(digitalRead(led));
  delay(1000);
}

void serialEvent() {
  if (Serial.read() == 'H' || Serial.read() == 'h') {
    digitalWrite(led, HIGH);
  }
  
  if (Serial.read() == 'L' || Serial.read() == 'l') {
    digitalWrite(led, LOW);
  }
  
}