Mistakenly I dropped the answer in the comment section. Sorry to bother you. ---- 1 is not legitimate. The usage of ところで here has to be used to describe supposition; 2年間日本語を勉強したところで、上手に話すことはできない (Even if you learn Japanese for two years, you won't be able to speak it fluently.) On the other hand, 2 is perfect; Even though I learned Japanese for two years, I'm still not good at. Now you know the difference. ところで means 'even if' only used in the subjunctive mood, and 'のに' is 'even though'.

1 is not legitimate. The usage of ところで here has to be used to describe supposition; 2年間日本語を勉強したところで、上手に話すことはできない (Even if you learn Japanese for two years, you won't be able to speak it fluently.) On the other hand, 2 is perfect; Even though I learned Japanese for two years, I'm still not good at. Now you know the difference. ところで means 'even if' only used in the subjunctive mood, and 'のに' is 'even though'.