The TNT revamp has struggled in its second year, with ratings in the US falling under 2 million.
"I'm optimistic about a season three," Duffy told TV Guide. "But only based on the fact that I don't believe that the directors, writers and actors and that every other person involved in making Dallas could make a better television show called Dallas."
He added: "I think writing for the last episode of [season two] is one of the best executions of a cliffhanger in the history of Dallas."
Duffy added that he remains proud of Dallas despite the show's declining viewership.
"If we were, for some strange reason, not to get picked up, I wouldn't feel bad at all because I feel so good about what we've done," said the 64-year-old, who has played Bobby Ewing since 1978.
In the UK, Dallas was shifted to a late-night slot by Channel 5 after ratings fell.
> Dallas exec on JR murder plot: 'There's a delicious reveal'
Watch a promo for season two of Dallas below: