A row erupted after council proposals for new contracts for more than 2,000 staff that would result in wage cuts of up to 23%.
The authority fears it could face equal pay claims from other employees if it does not make the cuts.
Hundreds attended a rally to "celebrate the work of Durham's teaching assistants".
Claire Williams, Northern Regional Secretary of Unison said: "There is positive progress being made... we are really keen to  get a resolution to this dispute quickly for our teaching assistants as it's been a very stressful year for them."
The new contracts were originally proposed for January but after industrial action in November the plan was suspended.
Members of the Unison and ATL unions were due to strike again for three days in December but that was called off to restart talks.
The council says its review of the matter should be completed in September.
Talks held between teaching assistant unions and Durham County Council are "progressing positively", Unison said.