SQL and XPath queries support both score constructions jcr:score and jcr:score()

SELECT * FROM nt:base ORDER BY jcr:score [ASC|DESC]
SELECT * FROM nt:base ORDER BY jcr:score()[ASC|DESC]

//element(*,nt:base) order by jcr:score() [descending]
//element(*,nt:base) order by @jcr:score [descending]

Do not use "ascending" combined with jcr:score in XPath. The following XPath statement may throw an exception:

... order by jcr:score() ascending

Do not set any ordering specifier - ascending is default:

... order by jcr:score()