I think you made a typo when you wrote 10.0". Did you mean 0.10"?
The answer to your question is two-fold.
##Current document, i.e. set this default only for the new or edited document
In principle, text in a document is formatted under paragraph style Text Body. You can then customise this style to change its spacing below to 0. It will also affect all styles derived from it, those used for formatting body paragraphs, excluding headings which are in a parallel hierarchy.
To modify an existing style (or create a custom one), display the style side pane with F11 (except under MacOS X because this key is intercepted by the OS, in which case, use Styles>Manage Styles. Right click on a style name and Modify. If you choose, New, you create a new style which is initially the same as the one you clicked on.
Explore the various tab.
In case, you want to force this zero-spacing for all styles, including the headings, TOC, Indexes, … do the customisation on Default Style.
Note that contrary to other office suites, Default Style in Writer is not the standard style for the discourse. This Default Style is reserved for setting defaults applicable to all other styles. Modifying it exposes you to unexpected consequences, notably with headings or footnotes.
##For all your future documents
Create an empty document (or with a content you’d like to have included in all your future documents) where you customise the styles and even add your preferred custom ones. Don’t save this file the usual way, but with File>Template>Save as Template. Give it a name and it will be stored in a Writer-known location. For ease of editing, save it also in your home directory with File>Save As, giving it a name with extension .ott (very important so that the document is later considered a template).
To make the newly saved template in the Writer location your default template, File>Templates>Manage Templates, right-click on the desired one and Set as Default.
This is a very quick description. For detailed information, read the freely downloadable Writer Guide. Chapters 8 & 9 are dedicated to styles; chapter 10 to templates.
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