That's not in the OGL 1.0(a) license, that looks like it's from the Open Content declaration which publishers write themselves."Open Content: Except for material designated as Product Identity, the materials in this book are Open Game Content and may be reproduced in any form without written permission."
If someone put that text in a book, that looks like they've legally granted you a single-line license outside of OGL 1.0(a). Hopefully, they have not included OGC they do not own in that book, because that single-line license cannot grant rights to other people's copyrighted work.
To use content that was released under OGL 1.0(a) (and not providing the option of any additional license - a very tiny minority, such as the work you quoted from, may have that option), you need to use OGL 1.0(a) (or 1.0, as both are "approved") in your work.