How can I light one led from two different sensors?
int ledPin = 13;

int ldrPin = A0;

int PIR_Pin = 2; 

void setup() 

{  

    Serial.begin(115200);

    pinMode(ledPin, OUTPUT);

    pinMode(PIR_Pin, INPUT); 


    Serial.println("Started Monitoring!");
} 

void loop() 
{ 


    boolean lightStatus = ( analogRead(ldrPin) &lt;= 400 ) ;
    digitalWrite(ledPin,  lightStatus);

    if(lightStatus) Serial.println("Light Triggered!");

    if(digitalRead(PIR_Pin) == LOW)
    {
         Serial.println("Motion Triggered!");
         digitalWrite(ledPin, HIGH);
         delay(5000);
         digitalWrite(ledPin, LOW);
     }
}


To keep it simple serial code is removed, if needed can be added easily that should not be a big issue. 
Still this can be done in much more efficient way. This is just one solution.

Note: haven't complied/error checked the code as i am writing this on a phone. Hope it should work as intended, errors if any, shall be minor ones.  Comment below if any issues.

Update 1: added code to send triggered status over serial comm.

Update 2: corrected "Boolean" to be as "boolean"