How to make correct selection for Cursor android?

I am rather new in android and SQLite, so please don't be so strict :)

I need to select rows from db, where some String length must be > than 5 symbols.

Here is part of my code:

@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
    mProgressBar.setVisibility(View.VISIBLE);
    mProgressBar.start();
    return new CursorLoader(
            getActivity(),
            mUri,
            CONTACT_COLUMNS,
            mSelection, null, null
    );
}

So any ideas how my mSelection must looks like?

Great thanks for all advises!