The phrase "a long and ongoing" is correct and usable in written English.
It can be used to describe a situation, process, or relationship that has been occurring for an extended period and continues to persist.
Example: "The project has been a long and ongoing effort to improve community resources."
Alternatives: "a lengthy and continuous" or "an extended and persistent".
Recovering from BDD is a long and ongoing process, made up of lots of small steps, but moving to university definitely made a huge difference.
There is a long and ongoing debate on whether this type of hippocampal damage, referred to as hippocampal sclerosis, is the cause or consequence of TLE.
A long and ongoing series of studies showed that adiponectin causes muscle to burn fatty acids faster—so they are not stored as fat and increases the metabolism of the sugar glucose.
In addition to the grand crypto-anarchist vision, there is also a long and ongoing line of academic work on privacy-preserving versions of different types of computations, promising more modest privacy enhancements in various specific domains.
The influence that facial features have in our life has spurred a long and ongoing interest in unraveling the roles that genes and environment play in the morphological characteristics of the human face.
Having been at more historic events and met more famous people at their most vulnerable than most, Scottish photographer Harry Benson has had a long and ongoing career.
The idea for 596 Acres grew out of a long and still ongoing effort to convert a city-owned site in Clinton Hill into a park.
Georgia Tech students hold a heated, long and ongoing rivalry with the University of Georgia, known as Clean, Old-Fashioned Hate.
Represented by a mascot named Buzz, the teams have a long, heated and ongoing rivalry (referred to as "Clean, Old-Fashioned Hate") with the University of Georgia.
In the latest development in a long and complicated series of ongoing lawsuits between the two companies, Judge Lucy Koh has found that Samsung did not willfully infringe Apple patents.
Political corruption has a long and storied (and, sadly, ongoing) history in New York which reaches back farther than even Boss Tweed, so it'd be pretty easy to fill such a museum with exhibits, one assumes.
