Thanks for the tip David. Now I do this:

second = DS1307_get(SEC);
FirstDigit = second & 0xF;

 

But I keep getting the same value all the time (the value that I have originally set). I am not sure the timer has started... even though I start it with

void DS1307_startTimer()
{
	I2C_start();
	I2C_write(DS1307_ID); /* connect to DS1307 */
	I2C_write(0x00); /* Request RAM address at 00H */
	I2C_write(0x80); /* Set CH bit ie. 7th bit og 0x00 to start timer*/
	I2C_stop();           /* Stop i2c bus */
}