How to hide Series label in a chart

Hello,
I have a Chart with one series as values.
The chart is good and I can see the series label in the corner.
I can hide it by uncheck the "show legend.

Now I added another value to my chart and got another series label.

Is there a way to hide only one label?
If I use =" " in the "series label" of that data then the label its self is hidden but the label mark is still visible.

Thanks.Was my question not clear enough or maybe there isn't any solution for the problem?

I'll be glad to hear your opinion.

Thanks.