The longer length of the loan would increase the amount of the interest paid.
Example a $2000 loan at 3% for 6 months would add $360 (2000x.03 =$60 a month. $60 x 6 =$360 Total interest for 6 months.
The same loan for 12 months would cost
$60 x12= $720.
So for 6 months total you would pay on an $2000 loan would be $2360, and for 12 months would be $2720.