Democrats across Ohio are pleading for help in the state’s Senate contest, afraid they may lose a winnable election unless national party leaders make major investments in the coming days. So far, the most powerful groups in Democratic politics have prioritized Senate pickup opportunities in North Carolina, Wisconsin and Pennsylvania over Ohio, once a perennial swing state that veered right in the Trump era. But on the eve of the 2022 midterms, some public polls suggest Ohio is as competitive as the other swing states, leaving many Democrats here wondering why their party isn’t backing Senate contender Tim Ryan more forcefully. The financial disparities in the race are stark. Republican JD Vance, a venture capitalist and author of “Hillbilly Elegy,” is the beneficiary of more than $30 million from outside Republican groups. They include organizations aligned with former President Donald Trump and Senate Republican Leader Mitch McConnell. By contrast, Ryan has benefited from less than $4 million in outside spending so far.