Read pushbutton and light LED

Hello, I am programming the Baby O, trying to read a port connected to a pushbutton and light the LED. Why is this code not working?

Thanks for all help and comments!

int main(void) {
	DDRD |= 1<<PD1;					// set PD1 to output
	while(1){
	        if bit_is_set(PORTB,PB3){
			PORTD |= 1<<PD1;			// LED on
		}
	}
	
	return 0;
}

Hello,

You need to use PINB to read port B.

- Jan