How to know if a led is turn on

Other Hardware LEDs and Multiplexing
1

Hi
I know the question sounds simple. But
I want to know if it is possible to know when a led is turn on.

int LED=13;
void setup() {
  pinMode(LED, OUTPUT);
  digitalWrite(LED, HIGH);
}

void loop()
{
 digitalWrite(LED, LOW);    
}

In this example I am turning of the LED. But I will like that this line digitalWrite(LED, LOW); only takes place when the led is on.

Any ideas?

2 
if (digitalRead(LED)==HIGH) {
  digitalWrite(LED, LOW);    
}
3 
void loop()
{
 if(digitalRead(LED) == 0 ) digitalWrite(LED, HIGH);  else digitalWrite(LED, LOW);    
}

However, this will turn on and off so rapidly it will look like it is on all the time.

4

Thanks a lot.