Leeds, who were the better side in the first half and missed a number of chances at the City Ground, were sunk by Brennan Johnson's goal to make it seven games without a win and they are only out of the relegation zone on goal difference.
That run looks unlikely to improve in the next week with a quickfire double-header with Manchester United.
"I take full responsibility, I have to find a way of turning good performances more into winning because that's exactly where we are and have been for a little while," Marsch said.
"That is the last step for the potential of where we need to be at.
"It is my responsibility and I understand their frustration and I accept it, I have to find a way to turn a lot of the good things that are happening into results or we find ourselves in a stressful situation. I understand.
"It's difficult to have the right words for the team on exactly what is needed right now because the emotion is too much, it is a big week, it is a huge week.
"I understand the frustration and doubts, internally we have belief here, we do.
"The players are all in, they have given everything they have, we are young and we are trying to put it all together, but I have to find a way right now that come Wednesday we are ready for a big result.
"Everyone is aligned, when we don't get results we get stressed and then instead of managing development we are managing stress. I am focused entirely on how to help the group in these moments to be what I know they can be."