need help with escape room puzzle im working on

Hello Everyone, im new here, im working on a escape room puzzle, i have a chessboard, on the back of it, is a hall sensor.so if you place the right piece on the right spot the arduino sends a command to the relay and then the electric lock opens up. The problem im having is, if you place the chess piece on the board, the power on the lock stay on. Been struggling with this for days already. The code for the project is as follow

int hallSensorPin = 2;    

int ledPin =  13;    

int state = 0;          

void setup() {

  pinMode(ledPin, OUTPUT);      

  pinMode(hallSensorPin, INPUT);    

}

void loop(){

  state = digitalRead(hallSensorPin);

  if (state == LOW) {        

   digitalWrite(ledPin,LOW);

  }

  else {

  digitalWrite(ledPin, HIGH);

  }

}