Not sure if I understand your question. Is this what you are looking for?
df <- dist_tab(x)
df.melt <- melt(df, id.vars="interval", measure.vars=c("Freq", "cum.Freq"))
#
ggplot(df.melt, aes(x=interval, y=value, fill=variable)) +
geom_bar(stat="identity", position="dodge")