Answer

1. You may terminate the contract after 12 months by giving 2 months notice.
2. After 12 months, you can give 2 months notice and terminate the contract.

The second statement says that notice to terminate the contract can be given only after 12 months. So in effect the minimum duration of the contract is 14 months. This is different with the first statement, which says that the contract can be terminated after 12 months, provided that 2 months notice has been given. There is no requirement that the notice has to be given only after 12 months, so the minimum duration of the contract is 12 months, provided that notice is given after 10 months (or earlier in common practice). This is something to watch out for when you sign a rental contract in the future!